[decompiler] as-type and font method support (#3855)

Add support for `as-type` macro, and detecting inline font methods. This
works in all three games but I've only updated jak 3's goal_src for now.
Eventually I will go back and work through the others, but I want to get
more decompiler features in first.


![image](https://github.com/user-attachments/assets/5c31bf85-97b4-437c-bc4b-dc054e60551e)

---------

Co-authored-by: water111 <awaterford1111445@gmail.com>

goal_src/jak2/kernel/gcommon.gc

@@ -323,6 +323,19 @@
     ,@args)
   )
 
+(defmacro as-type (this type)
+  "If this is the specified type, return this cast to that type. Otherwise, return #f."
+  (with-gensyms (obj)
+    `(the ,type (let ((,obj ,this))
+                  (if (type? ,obj ,type)
+                      ,obj
+                      )
+                  )
+          )
+    )
+  )
+
+
 (defun ref ((arg0 object) (arg1 int))
   "Get the n-th item in a linked list. No range checking."
   (dotimes (v1-0 arg1)